1. Field of the Invention
The present invention is a method to connect an electronic component in order to test it and mount it on a substrate (circuit or package) as well as a device to implement this method.
2. Description of the Prior Art
It is known that electronic components should be tested and debugged before being mounted if this mounting is to be done efficiently. This is especially important for complex integrated circuits. For simplicity's sake, only "testing" shall be referred to in the rest of this text, it being understood that this term also includes debugging. These components should be tested preferably throughout the temperature range of their use, under voltage and at the clock frequency of the integrated circuit.
To mount a component on a substrate (circuit or package), in the standard wiring method, each of the connection pads of the component is connected to a pad of the substrate by means of conducting wires. In this case, to test the component before it is mounted, conducting probes, connected to the testing instruments, are used. These conducting probes are placed in mechanical and electrical contact with the pads of the components. This method has inadequacies and flaws. These probes do not provide for entirely satisfactory tests, particularly because they introduce unwanted phenomena: in particular, they cannot be used for high frequency testing (at a few tens of MHz for example). Furthermore, they leave dents on the pads to which they are applied. These dents make the pads brittle and may cause them to be damaged. The result of this is that the component often has to be tested at least partly after it is mounted. This necessitates repairs which increase in number and, therefore, become lengthier and costlier in proportion to the complexity of the component.
Another method is that of the prior art technique known as the tape automatic bonding (TAB) technique, described in greater detail below. This technique consists mainly in placing the component on a tape, arranged so that the component can be tested before it is mounted. However, the TAB method has disadvantages. Mounting the component on the tape makes it necessary to have projections. These projections have to be made on the connecting pads of the component so that the conductors carried by the tape can be soldered. This is a fairly lengthy and costly operation. Furthermore, a portion of the tape is usually left around the component after the test, thus making the component more bulky.